Studies on seasonal abundance and distribution of Vibrio and related species from a water supply in a cholera endemic area (Bangladesh) will be continued. Isolated strains will be subjected to extensive numerical analysis, examined for enteropathogenicity and antibiotic resistance patterns, and analyzed for presence of extrachromosomal genetic elements. The relationship of NAG strains of V. cholerae isolated from the water supply and from the Chesapeake Bay to classical and El Tor V. cholerae will be studied by systematic analysis and DNA/DNA hybridization studies. Analysis of enterotoxic factors of NAG vibrios, of V. parahaemolyticus and of Aeromonas hydrophila will be pursued on both ecological and molecular genetic bases. Correlations will be sought between individual strain characteristics and presence of extrachromosomal elements, and factors relating to pathogenicity and natural distribution. By using a computer based system, development of an online identification system for Vibrio species will be developed.